1. Field of the Invention
The present invention relates to a video camera in which a zooming can be effected by an electronic zoom means.
2. Description of the Related Art
There have heretofore been proposed video cameras having an electronic zoom means in which data representing a picked-up video signal is written in a memory and a zooming is effected by arbitrarily determining the order at which the above-mentioned memory is read out.
In such video cameras, the conventional electronic zoom enlarges or reduces a magnification in a certain constant increasing width of magnification so that the magnification can be constantly reduced or enlarged only at a constant zoom speed. When the magnification is constantly reduced or enlarged only at a constant zoom speed, there is then a problem when the conventional electronic zoom is operated in a ganged relation with an optical zoom into which a variable speed zoom, in particular, was already introduced.
More specifically, in the video camera in which the optical zoom and the electronic zoom are provided together, when the optical zoom is changed to the electronic zoom, a picture is disturbed at the connected portion between the optical zoom and the electronic zoom because the zoom speeds of the optical zoom and the electronic zoom are different. In order to avoid the aforesaid shortcomings, the conventional video cameras are arranged such that the optical zoom is changed to the electronic zoom after the speed of the optical zoom is progressively decreased to reach the same zoom speed as the electronic zoom.
According to the above conventional method, however, the zoom speed is freely changed even though a zoom lever is not operated. As a result, the user cannot help feel a sense of incompatibility and a sense of discontinuity when the optical zoom and the electronic zoom are operated in a ganged relation. Thus, the video camera user cannot remove a feeling of unnaturalness completely.
Further, there are our copending European laid-open patent publications Nos. 0475840, 0485302 and 0560549 which will be briefly described below.
European laid-open patent publication No. 0475840 describes an inner focus type lens driving apparatus in which a coil for a velocity sensor is wound around a voice coil system linear actuator coil in an overlapping fashion. European laid-open patent publication No. 0485302 describes a camera lens barrel in which a zoom lens portion of an inner focus system is a quartet zoom lens. A stepping motor is driven in a micro-step fashion having a low noise and a low vibration when a low speed zooming is effected, and driven in a high torque pulse driving fashion when a high speed zooming is effected. According to this previously-proposed application, a driving speed of the driving system can be increased, a lifetime thereof can be extended, a noise thereof can be reduced and a vibration thereof can be reduced. This lens barrel for a camera is used in a small-sized camcorder. Furthermore, European laid-open patent publication No. 0560549 describes a camcoder in which when an optical viewfinder zoom and an electronic zoom are used together, a picture frame whose size is changed in accordance with a magnification of the electronic zoom is displayed on a viewfinder so that an actual shooting range can be displayed on the viewfinder accurately.